How to pass environment variables to CNI Addon?

Question

- We use Terraform to automate the creation of our EKS Clusters.
- We use the CNI `aws_eks_addon` to setup CNI on our EKS Nodes.
- We need to configure various environment variables on the CNI Node (ex. `WARM_IP_TARGET`).
- We strive to avoid null resources, and are looking for a way to configure these variables directly via the AWS Addon. 
- What is the best way to set these environment variables as part of our Terraform Configuration? Would you consider extending the Addon API endpoint to allow customization of these variables?

Answer

Hello there,

You can set these environment variables as part of your Terraform Configuration. To have flexibility in configuring the env of the CNI, you can set the env outside of your Terraform Configuration as well.
You can also write a script that will generate all the env you want to set using the `kubectl` command. Use Terraform to launch the script.
To set `WARM_IP_TARGET` to 5 for example, you can use the command below:
```
kubectl set env ds aws-node -n kube-system WARM_IP_TARGET=5
```
See more info on the [CNI ENVs](https://github.com/aws/amazon-vpc-cni-k8s#warm_ip_target)

How to pass environment variables to CNI Addon?

Relevant content